They've really shifted how Outlook works... as well as how the backend is more tuned to the way M365 mail works far more than how it used to work with Exchange, or independently. It's been a slow downslide imo since around 2007 or so.

I know the why, but it's really worse as an experience for most people than the older integrations... but the use of horizontally scalable backends makes for a saner platform at the expense of better UX.